With the development of network technology, various types of new networks continuously occur, for example, a Wireless Fidelity (WiFi) network and a Worldwide Interoperability for Microwave Access (WiMAX) network.
Both the WiFi and the WiMAX are important wireless broadband access technologies, but each has advantages and disadvantages. For the WiFi, network layout is fast, cost is low, a bandwidth is high, a spectrum can be used without authorization, but coverage is small. WiMAX has large coverage, but many users exist in the large coverage and an average user bandwidth is reduced. Therefore, it is recently researched to use the WiFi as a supplement for the WiMAX and use a WiFi access point (AP) at places having a weak WiMAX signal or being populous.
Thus, a problem of handover of a user terminal between the WiFi network and the WiMAX network is involved. A part of existing user terminals support double-radio frequency handover. During the handover of the part of the user terminals, two radio frequency circuits work at the same time. One radio frequency circuit communicates in a current network and the other radio frequency circuit performs a network access operation in a target network, so as to implement seamless handover.
However, for user terminals that do not support the double-radio frequency handover but only support single-radio frequency handover, in order to ensure to implement seamless handover, a common handover mode in the prior art is described in the following.
Firstly, a virtual AP is deployed in a public network. A user terminal establishes a tunnel with the virtual AP through an AP in a current network and executes a handover operation with the virtual AP through the tunnel, that is, the user terminal accesses the network from an air interface of a target network. After entering the target network, the user terminal is handed over from the virtual AP to a real AP of the target network (that is, intra-network handover), and thus network handover is implemented eventually.
However, the AP in the current WiFi network does not support a roaming function and a procedure of handover from one WiFi network AP to another WiFi network AP is unable to be completed, so that the intra-network handover in the existing handover method is not applicable to the WiFi network.